1. Field of the Invention
The present invention is broadly concerned with seed bins and metering gate devices used therewith in order to permit accurate dispensing of seed quantities. More particularly, the invention is concerned with such bins and devices wherein the metering gate includes a shiftable outlet gate member and apparatus to limit the travel of the gate member to a predetermined position for accurate seed dispensing.
2. Description of the Prior Art
Seed dealers commonly store quantities of various seeds in individual, upright seed bins, each holding several tons of seed. These bins typically include an upright cylindrical primary section along with a frustoconical outlet section for delivery of seed to an underlying conveyor belt or similar expedient. The frustoconical sections of the bins are provided with a movable, primary gate allowing flow of seed from the bin. A secondary gate assembly is provided beneath the primary gate, which receives seed upon opening of the primary gate. The secondary gate assembly has a hopper along with a flat, shiftable gate member which is moved between closed and open positions by means of a piston and cylinder assembly, in order to create a delivery passageway. In practice, the primary gate is opened to a desired degree, and the secondary gate is fully opened for a time interval estimated to dispense the requisite amount of seed.
A significant problem with these bins and seed delivery devices is the inability to accurately dispense quantities of seeds. Shifting of the primary gate necessarily creates an at least partially arcuate seed flow opening, owing to the circular cross-section of the frustoconical outlet section of the bin. Seed from this arcuate opening is then delivered to the fully opened underlying secondary gate assembly. Thus, the rate of seed flow from the bin is determined solely by the position of the primary circular gate, with no flow control provided by the secondary gate assembly. Experience has proved that the primary gate cannot be accurately and reproducibly positioned so as to deliver seed at the same rate during each opening thereof. Thus, either too much or too little seed may be dispensed during identical gate-open intervals.